Calculating Timber Quantities

You should be aware that timber is available in many different species. From Acacia to Zebrano with many thousands of species in between. Some are available in Australia, many are not. Some are cheap and are available in solid form. Some are expensive and so are converted to veneers for veneered particleboard.
Some useful species are best suited to outdoor use and some are not. The ability to choose the right timber for the job will determine whether the client receives the job that they ordered and that you, as the maker, have made a profit or loss.
By choosing the right material and ordering the correct quantity, you will go a long way to ensuring that the business that you work in, stays in business.
The Key Competencies
Key Competencies are skills you will need master in order to function competently within your organisations. The key competencies are reinforced through practice exercises.
The key competencies have been identified for trade theory and calculations as:

• Collecting, analysing and organising ideas and information; taking measurements and making estimations, reading plans.
• Using mathematical ideas and techniques;

The basics of measurement and calculations
Measuring tools:




Before we can start to understand how to calculate timber quantities it is important to understand that in the Off site construction industry measurements and calculations for timber products are made using millimetres and metres only.
Centimetres are NOT used in our industry.
With this in mind it is necessary to be able to convert Millimetres into metres and metres in to millimetres by placing the decimal point in the correct place

POSITIONING OF THE DECIMAL POINT

In the Shopfitting, Kitchens and Detail Joinery industry we calculate surface areas in square metres (M2). The reasons we do this is because:

1. If we calculated in square millimetres, we would require a lot of space for all the numbersused. For example1000mm X 1000mm= 1,000,000 mm2

2. All of the suppliers of sheet materials e.g. particle boards and laminate,
price their products by the square metre.

So, to simplify our calculations we convert our millimetre dimensions into decimals of a metre.

for example:we say
1000mm=1.0mor5000m=5.0m
100mm= 0.1mor500mm= 0.5m
10mm= 0.01mor 50mm = 0.05m
1mm=.001mor5mm= 0.005m
Download and print the following document and try the exercises in the document

converting decimal points.pdf

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When working on trade calculations you need to obtain a copy of the OFF-SITE CONSTRUCTION, FURNITURE,GLASS & GLAZING MATERIAL CALCULATIONS & COSTING textbook from your local library or TAFE Campus bookshop (order code: OSFGG07/1) - your trainer can assist you in obtaining a copy

You can download and work through the following workbook exercises to help you understand the basic on calculating timber quantities.

CALCULATIONS EXERCISES -

- Calculating labour and material cost exercises -
- Cutting patterns exercises -
- Surface area of Circles -
- Surface area of Triangles -

Use this cutting costing sheet template to make cutting lists and prepare costings.

Other calculations that will be useful include:

Calculating the circumference (distance around the outside) of a circle
the formaula is - circumference = 2 x Pi x radius of the circle or alternatively Pi x diameter of the circle:
watch this video to see how it works:


Here's a little video that may help understand and remember the basic circle formulae a little better. Thanks Mr Johnson.

Pythagoras Theory:

Pythogoras theory is used for calculating the length of the hypotenuse (or the longest side) in a right angle triangles:
Watch this video to see how the calculation works:


Then:
Download, read and do the exercises in the document below.